Physically alternating sense amplifier activation

ABSTRACT

A memory device having banks of sense amplifiers comprising two types of sense amplifiers. A first driver used to activate the first type of sense amplifier is embedded into a first bank. A second driver used to activate a second type of sense amplifier is embedded into a second bank. This alternating physical placement of the first and second sense amplifier drivers within respective banks is repeated throughout the device. This alternating physical arrangement frees up the gaps and mini-gaps for other functions, reduces the buses used for sense amplifier activation signals and allows large drivers to be used, which improves the operation of the sense amplifiers and the device itself.

This application is a continuation of application Ser. No. 10/771,436,filed on Feb. 5, 2004, now U.S. Pat. No. 6,862,229, which is acontinuation of application Ser. No. 10/075,763, filed on Feb. 15, 2002,now U.S. Pat. No. 6,707,729, which are hereby incorporated by referencein their entirety.

FIELD OF THE INVENTION

The present invention relates to the field of semiconductor memorydevices and, more particularly to a physically alternating senseamplifier activation scheme for a semiconductor memory device.

BACKGROUND OF THE INVENTION

An essential semiconductor device is semiconductor memory, such as arandom access memory (RAM) device. A RAM device allows the user toexecute both read and write operations on its memory cells. Typicalexamples of RAM devices include dynamic random access memory (DRAM) andstatic random access memory (SRAM).

DRAM is a specific category of RAM containing an array of individualmemory cells, where each cell includes a capacitor for holding a chargeand a transistor for accessing the charge held in the capacitor. Thetransistor is often referred to as the access transistor or the transferdevice of the DRAM cell.

FIG. 1 illustrates a portion of a DRAM memory circuit containing twoneighboring DRAM cells 10. Each cell 10 contains a storage capacitor 14and an access field effect transistor or transfer device 12. For eachcell, one side of the storage capacitor 14 is connected to a referencevoltage (illustrated as a ground potential for convenience purposes).The other side of the storage capacitor 14 is connected to the drain ofthe transfer device 12. The gate of the transfer device 12 is connectedto a signal known in the art as a word line 18. The source of thetransfer device 12 is connected to a signal known in the art as a bitline 16 (also known in the art as a digit line). With the memory cell 10components connected in this manner, it is apparent that the word line18 controls access to the storage capacitor 14 by allowing or preventingthe signal (representing a logic “0” or a logic “1”) carried on thestorage capacitor 14 to be read to or written from the bit line 16.Thus, each cell 10 contains one bit of data (i.e., a logic “0” or logic“1”).

Referring to FIG. 2, an exemplary DRAM circuit 40 is illustrated. TheDRAM 40 contains a memory array 42, row and column decoders 44, 48 and asense amplifier circuit 46. The memory array 42 consists of a pluralityof memory cells (constructed as illustrated in FIG. 1) whose word linesand bit lines are commonly arranged into rows and columns, respectively.The bit lines of the memory array 42 are connected to the senseamplifier circuit 46, while its word lines are connected to the rowdecoder 44. Address and control signals are input into the DRAM 40 andconnected to the column decoder 48, sense amplifier circuit 46 and rowdecoder 44 and are used to gain read and write access, among otherthings, to the memory array 42.

The column decoder 48 is connected to the sense amplifier circuit 46 viacontrol and column select signals. The sense amplifier circuit 46receives input data destined for the memory array 42 and outputs dataread from the memory array 42 over input/output (I/O) data lines. Datais read from the cells of the memory array 42 by activating a word line(via the row decoder 44), which couples all of the memory cellscorresponding to that word line to respective bit lines, which definethe columns of the array. One or more bit lines are also activated. Whena particular word line is activated, the sense amplifier within circuit46 that is connected to the proper bit lines (i.e., column) detects andamplifies the data bit transferred from the storage capacitor of thememory cell to its bit line by measuring the potential differencebetween the activated bit line and a reference line which may be aninactive bit line. The operation of DRAM sense amplifiers is described,for example, in U.S. Pat. Nos. 5,627,785; 5,280,205; and 5,042,011, allassigned to Micron Technology Inc., and incorporated by referenceherein.

The sense amplifier circuit 46 used in DRAM devices is typicallyarranged as banks of individual sense amplifiers. Common connections areused to activate the banks of sense amplifiers. A bank of senseamplifiers has many, e.g., two hundred and fifty-six, sense amplifiersadjacent to each other. FIG. 3 illustrates a typical sense amplifier 46found in a DRAM sense amplifier bank. The sense amplifier 46 includesfour isolating transistors 80, 82, 88, 90, two input/output (I/O)transistors 84, 86, a p-sense amplifier circuit 70 and an n-senseamplifier circuit 60.

The first isolating transistor 80 is connected such that its source anddrain terminals are connected between a first sense amp line SA and afirst bit line DL_(a). The first bit line DL_(a) is also connected tomemory cells (not shown) within the memory array 42 (FIG. 2). Similarly,the third isolating transistor 88 is connected such that its source anddrain terminals are connected between the first sense amp line SA and asecond bit line DL_(b). The second bit line DL_(b) is also connected toadditional memory cells (not shown) within the memory array 42 (FIG. 2).The second isolating transistor 82 is connected such that its source anddrain terminals are connected to a second sense amp line SA_(—) and athird bit line Dl_(a) _(—) , which during a sensing operation istypically driven to a complementary state relative to the first bit lineDL_(a). The third bit line Dl_(a) _(—) is also connected to memory cells(not shown) within the memory array 42 (FIG. 2). The fourth isolatingtransistor 90 is connected such that its source and drain terminals areconnected to the second sense amp line SA_(—) and a fourth bit lineDl_(b) _(—) . The fourth bit line Dl_(b) _(—) is also connected tomemory cells (not shown) within the memory array 42 (FIG. 2).

The gate terminal of the first and second isolating transistors 80, 82are connected to a first isolation gating line ISO_(a) _(—) while thegate terminal of the third and fourth isolating transistors 88, 90 areconnected to a second isolation gating line ISO_(b) _(—) . All four ofthe isolating transistors 80, 82, 88, 90 are n-channel MOSFET (metaloxide semiconductor field effect transistor) transistors. The isolatingtransistors 80, 82, 88, 90 and the isolation gating lines ISO_(a) _(—) ,ISO_(b) _(—) form isolation devices. The normal state for the isolationgating lines ISO_(a) _(—) , ISO_(b) _(—) is a high signal. For the senseamplifier 46 that is adjacent to the selected memory array 42, theisolating transistors 80, 82, 88, 90 that do not connect directly to theselected array are driven to ground (via the isolation gating linesISO_(a) _(—) , ISO_(b) _(—) ). This isolates the deselected array fromthe active sense amplifier.

The first I/O transistor 84 is connected between a first I/O line IO andthe first sense amp line SA and has its gate terminal connected to acolumn select line CS. The second I/O transistor 86 is connected betweena second I/O line IO_(—) and the second sense amp line SA_(—) and hasits gate terminal connected to the column select line CS. The I/Otransistors 84, 86 are also n-channel MOSPET transistors. The I/O linesIO, IO_(—) are used by the circuit 46 as a data path for input data(i.e., data being written to a memory cell) and output data (i.e., databeing read from a memory cell). The data path is controlled by thecolumn select line CS, which is activated by column decoder circuitry 48(FIG. 2) of the DRAM.

The p-sense amplifier circuit 70 includes two p-channel MOSFETtransistors 72, 74. The n-sense amplifier circuit 60 includes twon-channel MOSFET transistors 62, 64. The first p-channel transistor 72has its gate terminal connected to the second sense amp line SA_(—) andthe gate terminal of the first n-channel transistor 62. The firstp-channel transistor 72 is connected between the second p-channeltransistor 74 and the first sense amp line SA. The second p-channeltransistor 74 has its gate terminal connected to the first sense ampline SA and the gate terminal of the second n-channel transistor 64. Thesecond p-channel transistor 74 is connected between the first p-channeltransistor 72 and the second sense amp line SA_(—). A p-sense amplifierlatching/activation signal ACT is applied at the connection of the twop-channel transistors 72, 74.

The first n-channel transistor 62 has its gate terminal connected to thesecond sense amp line SA_(—) and is connected between the secondn-channel transistor 64 and the first sense amp line SA. The secondn-channel transistor 64 has its gate terminal connected to the firstsense amp line SA and is connected between the first n-channeltransistor 62 and the second sense amp line SA_(—). An n-sense amplifierlatching/activation signal RNL* is applied at the connection of the twon channel transistors 62, 64. The sensing and amplification of data froma memory cell is performed by the p-sense and n-sense amplifier circuits70, 60, respectively controlled by the p-sense and n-sense activationsignals ACT, RNL*, which work in conjunction to effectively read a databit which was stored in a memory cell.

FIG. 4 illustrates an exemplary portion of the DRAM circuit 40 havingbanks of sense amplifiers 46 _(a), 46 _(b), 46 _(c) and gaps 50 _(a), 50_(b) between the sense amplifiers 46 _(a), 46 _(b), 46 _(c). Althoughnot shown, the two sense amplifier activating signals RNL* and ACT(described above with reference to FIG. 3) are typically generated bydrivers located within the gaps 50 _(a), 50 _(b). FIG. 4 alsoillustrates three sub-arrays 42 _(a), 42 _(b), 42 _(c) of memory cellsand row drivers 52 _(a), 52 _(b), positioned between the sub-arrays 42_(a), 42 _(b), 42 _(c).

The gaps 50 _(a), 50 _(b) occupy a relatively small area of the DRAM 40compared to the amount of circuitry (e.g., RNL* and ACT drivers)necessary to be designed in the gaps 50 _(a), 50 _(b). There are anumber of design considerations that affect the gap design and thenumber of sense amplifiers in a bank of sense amplifiers. For example,the word line length is usually maximized to achieve the fewest numberof decoders while still meeting the DRAM chip's performancerequirements. If the word line is too long, then the RC delay becomesprohibitive. A second consideration is to keep the IR drop across theRNL* and ACT buses within acceptable limits. Both the RNL* and ACTsignal lines are connected to buses that stretch into the gaps. The IRdrop across these buses is a function of the number of sense amplifiersin the bank and the width of the RNL* and ACT buses. Because the areathat a sense amplifier occupies is minimized, the width of the RNL* andACT buses is constrained. A third consideration that will determine thenumber of sense amplifiers in a bank is the width of the RNL* and ACTdrivers that are placed into the gaps. The greater the number of senseamplifiers, the greater the width of the drivers.

In some prior designs, one of the RNL* or ACT drivers is placed into thesense amplifier, while the other driver is placed into the gap. The areaoccupied by the sense amplifier increases, but this tradeoff may be madefor many reasons: 1) additional driver size, i.e., a size beyond whatcould have fit into the gap, was needed and/or 2) busing requirementsthrough the sense amplifier were large enough that the additional arearequired for the driver transistors was free. Once one of the drivers isembedded into the sense amplifier, there is exists more area in the gapfor the other driver. This scheme, however, requires large senseamplifiers and circuitry in the gaps.

Placing the drivers into different gaps is another method thatpurportedly increases the widths of the RNL* and ACT drivers. That is,one gap would have the ACT driver and another gap would have the RNL*driver. This method reduces the amount of wasted chip area by separatingthe drivers. That is, because the ACT driver usually includes ap-channel transistor and the RNL* driver usually includes an n-channeltransistor, there is a minimum spacing requirement between the drivers(i.e., transistors). This space requirement between the n-channel andp-channel transistors (if implemented adjacent each other) is a largewasteful area that could have been used for additional driver width.Having the drivers in different gaps reduces this problem, but it is notan optimal solution particularly in light of new DRAM architectures.

New DRAM architectures, ones employing global word lines, make it verydifficult to have adequate device widths for the RNL* and ACT drivers.FIGS. 5 and 6 illustrate a typical global word line architecture/scheme100 and a DRAM 140 implementing the scheme 100. In the global word linescheme 100, one large row decoder/driver 102 replaces the multiplerepetitive decoders/drivers 52 _(a), 52 _(b) (FIG. 4) used in other DRAMarchitectures. The scheme 100 uses a metal global word line GLOBAL WL118 and a series of polysilicon sub-word lines SUB WL 118 _(a), 118_(b), 118 _(c), 118 _(d). In the global word line scheme 100, arraybreaks (or gaps) exist where the polysilicon sub-word lines SUB WL 118_(a), 118 _(b), 118 _(c), 118 _(d) are strapped to the metal global wordline GLOBAL WL 118.

The DRAM 140 implementing the global word line scheme 100 contains banksof sense amplifiers 46 _(a), 46 _(b), 46 _(c), 46 _(d), sub-arrays 42_(a), 42 _(b), 42 _(c), 42 _(d) of memory cells, row drivers 152 _(a),152 _(b), gaps 150 _(a), 150 _(b), mini-gaps 154 _(a), 154 _(b), 154_(c), 154 _(d) and word line contact blocks 156 _(a), 156 _(b), 156_(c), 156 _(d). The mini-gaps 154 _(a), 154 _(b), 154 _(c), 154 _(d) aremuch smaller than the gaps 150 _(a), 150 _(b) because they occur at theword line strapping areas (as a result of the global word line scheme100). The mini-gaps 154 _(a), 154 _(b), 154 _(c), 154 _(d),unfortunately, are too small to contain adequately sized RNL* and ACTdrivers. This forces the designer of the DRAM 140 to use inadequatesense amplifier drivers or to waste precious space on the chip toimplement adequate ones.

Accordingly, there is a desire and need to implement adequately sizedsense amplifier drivers that will improve sense amplifier operation in aDRAM memory device without wasting precious space in the device.

SUMMARY OF THE INVENTION

The present invention provides a DRAM memory device having relativelylarge sense amplifier drivers (i.e., RNL* and ACT drivers), whichimprove the operation of the device's sense amplifiers, reduce the sizeof the buses used for the sense amplifier activation signals and free upspace in the device for additional functionality.

The above and other features and advantages are achieved by a memorydevice having banks of sense amplifiers comprising two types of senseamplifiers. A first driver used to activate the first type of senseamplifier is embedded into a first bank. A second driver used toactivate a second type of sense amplifier is embedded into a secondbank. No sense amplifier driver circuitry is contained within gaps ormin-gaps between the banks of sense amplifiers. This alternatingphysical placement of the first and second sense amplifier driverswithin respective banks is repeated throughout the device. Thisalternating physical arrangement frees up the gaps and mini-gaps forother functions, reduces the buses used for sense amplifier activationsignals and allows large drivers to be used, which improves theoperation of the sense amplifiers and the device itself.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages and features of the invention willbecome more apparent from the detailed description of exemplaryembodiments provided below with reference to the accompanying drawingsin which:

FIG. 1 is a circuit diagram illustrating conventional DRAM memory cells;

FIG. 2 is a functional block diagram illustrating a DRAM device;

FIG. 3 is a circuit diagram illustrating a typical sense amplifier usedin a DRAM device;

FIG. 4 is a block diagram illustrating a portion of a typical DRAMdevice;

FIG. 5 is a block diagram illustrating a portion of a global word linescheme for a DRAM device;

FIG. 6 is a block diagram illustrating a portion of a typical DRAMdevice implementing the global word line scheme illustrated in FIG. 5;

FIG. 7 is a circuit diagram illustrating an exemplary sense amplifierhaving an embedded RNL* driver;

FIG. 8 is a circuit diagram illustrating an exemplary sense amplifierhaving an embedded ACT driver;

FIG. 9 is a block diagram illustrating an exemplary DRAM deviceconstructed in accordance with an embodiment of the invention;

FIG. 10 is a circuit diagram illustrating a portion of an exemplary bankof sense amplifiers constructed in accordance with another embodiment ofthe invention;

FIG. 11 is a circuit diagram illustrating a portion of another exemplarybank of sense amplifiers constructed in accordance with anotherembodiment of the invention; and

FIG. 12 is a block diagram illustrating a processor system utilizing aDRAM constructed in accordance with the exemplary embodiments of theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following detailed description, reference is made to variousspecific embodiments in which the invention may be practiced. Theseembodiments are described with sufficient detail to enable those skilledin the art to practice the invention, and it is to be understood thatother embodiments may be employed, and that structural and electricalchanges may be made without departing from the spirit or scope of thepresent invention.

As set forth above, there is a desire and need to implement adequatelysized ACT and RNL* drivers in a DRAM device. Proper sizing of thesedrivers will improve sense amplifier operation and operation of the DRAMdevice itself. It is also desirable to implement these drivers withoutwasting precious space in the device.

One possible solution is to embed both the ACT and RNL* drivers intoeach sense amplifier of the banks of sense amplifiers. Although it wouldbe possible to obtain larger drivers, this scheme would take up anenormous amount of space in the device and is not desirable. Anotherpossible solution is to alternate ACT driver embedded sense amplifiersand RNL* driver embedded sense amplifiers within the same bank of senseamplifiers. That is, within the same bank of sense amplifiers there willbe sense amplifiers having the ACT driver and other sense amplifiershaving the RNL* drivers embedded therein. The sense amplifiers arealternated within the bank such that each ACT driver embedded senseamplifier is adjacent (via a min-gap) an RNL* driver embedded senseamplifier.

FIG. 7 illustrates an exemplary sense amplifier 146 having an embeddedRNL* driver 191. The RNL* driver 191 comprises an n-channel MOSFETtransistor 192 having its gate terminal connected to an n-senseamplifier control signal LNSA that is generated by conventional controlcircuitry within the DRAM device. The transistor 192 is connectedbetween a ground potential and the n-sense amplifier 60. The RNL* driver191 generates a low potential (i.e., ground) n-sense amplifieractivation signal RNL* when it receives the n-sense amplifier controlsignal LNSA. The n-sense amplifier activation signal RNL* is used toactivate the n-sense amplifier 60. As is known in the art, the n-senseamplifier activation signal RNL* can be driven to Vcc/2 during prechargeoperations. The other components of the sense amplifier 146 are the sameas the conventional sense amplifier 46 (FIG. 3) and are not describedfurther.

FIG. 8 illustrates an exemplary sense amplifier 246 having an embeddedACT driver 293. The ACT driver 293 comprises a p-channel MOSFETtransistor 294 having its gate terminal connected to an p-senseamplifier control signal LPSA* that is generated by conventional controlcircuitry within the DRAM device. The transistor 294 is connectedbetween a high potential (typically Vcc) and the p-sense amplifier 70.The ACT driver 293 generates the high potential (e.g., Vcc) p-senseamplifier activation signal ACT when it receives the p-sense amplifiercontrol signal LPSA*. The p-sense amplifier activation signal ACT isused to activate the p-sense amplifier 70. As is known in the art, thep-sense amplifier activation signal ACT can be driven to ground duringprecharge operations. The other components of the sense amplifier 246are the same as the conventional sense amplifier 46 (FIG. 3) and are notdescribed further.

There is a problem with alternating ACT driver embedded sense amplifiers246 and RNL* driver embedded sense amplifiers 146 in the same bank. Theproblem arises because the ACT driver embedded sense amplifiers 246require transistors 294 with larger n-well width than the RNL* driverembedded sense amplifiers 146. Due to spacing requirements, there mustbe a minimum amount of space between the n-well edge of the ACT driver293 and the n-channel transistor 192 of the RNL* driver 191. Thisprevents the two sense amplifiers 146, 246 from being physicallyadjacent to each other, which means more space is required to implementthis type of scheme, rendering the solution sub-optimal. Thus, anothersolution is required.

FIG. 9 is a block diagram illustrating an exemplary DRAM device 340constructed in accordance with an embodiment of the invention. In theillustrated embodiment, both RNL* driver embedded sense amplifier banks146 _(a), 146 _(b), 146 _(c), 146 _(d) and ACT driver embedded senseamplifier banks 246 _(a), 246 _(b), 246 _(c), 246 _(d) are physicallyalternated throughout the device 340. In the illustrated embodiment, thebanks 146 _(a), 146 _(b), 146 _(c), 146 _(d), 246 _(a), 246 _(b), 246_(c), 246 _(d) are physically alternated in the horizontal direction.For example, the top portion of the device 340 contains the third ACTdriver embedded sense amplifier bank 246 _(c), the first RNL* driverembedded sense amplifier bank 146 _(a), the first ACT driver embeddedsense amplifier bank 246 _(a), and the third RNL* driver embedded senseamplifier bank 146 _(c), positioned in the horizontal, left-to-rightdirection.

Each bank 146 _(a), 146 _(b), 146 _(c), 146 _(d) comprises a pluralityof RNL* driver embedded sense amplifiers 146 (FIG. 7). Each bank 246_(a), 246 _(b), 246 _(c), 246 _(d) comprises a plurality of ACT driverembedded sense amplifiers 246 (FIG. 8). Each bank 146 _(a), 146 _(b),146 _(c), 146 _(d), 246 _(a), 246 _(b), 246 _(c), 246 _(d) may comprisetwo hundred and fifty-six RNL* and ACT embedded sense amplifiers 146,246, respectively. It should be appreciated that the invention is notlimited to any specific number of sense amplifiers used in the banks.

The physical alternation of the RNL* driver embedded sense amplifierbanks 146 _(a), 146 _(b), 146 _(c) and ACT driver embedded senseamplifier banks 246 _(a), 246 _(b), 246 _(c) allows very large RNL* andACT drivers 191, 293 (FIGS. 7 and 8) to be used because the drivercircuitry is not placed within gaps 350 _(a), 350 _(b) or mini-gaps 354_(a), 354 _(b), 254 _(c), 354 _(d). Moreover, since the embodiment usesthe global word line scheme, the bus size for the n-sense amplifieractivation signal RNL* and p-sense amplifier activation signal ACT canbe very small, which leaves more area on the chip for power buses andother control signals routed over the sense amplifiers.

The illustrated device 340 implements the global word line scheme. Thus,it contains large row decoder/drivers 352 _(a), 352 _(b) (rather thanthe multiple repetitive decoders/drivers 52 _(a), 52 _(b) illustrated inFIG. 4), sub-arrays 42 _(a), 42 _(b), 42 _(c), 42 _(d), 42 _(e), 42_(f), 42 _(g), 42 _(h) of memory cells, gaps 350 _(a), 350 _(b), wordline contact blocks 156 _(a), 156 _(b), 156 _(c), 156 _(d) and mini-gaps354 _(a), 354 _(b), 354 _(c), 354 _(d). The gaps 350 _(a), 350 _(b) arephysically adjacent to and located over the row decoder/drivers 352_(a), 352 _(b) while the mini-gaps 354 _(a), 354 _(b), 354 _(c), 354_(d) are physically adjacent to and located over the word line contactblocks 156 _(a), 156 _(b), 156 _(c), 156 _(d).

It should be noted that the RNL* driver embedded sense amplifier banks146 _(a), 146 _(b), 146 _(c), 146 _(d) will supply the n-sense amplifieractivation signal RNL* to the ACT driver embedded sense amplifier banks246 _(a), 246 _(b), 246 _(c), 246 _(d) through a bus or contact blocks.This alleviates the need for the ACT driver embedded sense amplifierbanks 246 _(a), 246 _(b), 246 _(c), 246 _(d) to have their own RNL*driver. Similarly, the ACT driver embedded sense amplifier banks 246_(a), 246 _(b), 246 _(c), 246 _(d) will supply the p-sense amplifieractivation signal ACT to the RNL* driver embedded sense amplifier banks146 _(a), 146 _(b), 146 _(c), 146 _(d) through a bus or contact blocks.This alleviates the need for the RNL* driver embedded sense amplifierbanks 146 _(a), 146 _(b), 146 _(c), 146 _(d) to have their own ACTdriver. Thus, the illustrated embodiment does not require RNL* or ACTdrivers 191, 293 within the gaps 350 _(a), 350 _(b) or mini-gaps 354_(a), 354 _(b), 354 _(c), 354 _(d) of the device 340.

The first mini-gap 354 _(a) separates the first RNL* driver embeddedsense amplifier bank 146 _(a) from the first ACT driver embedded senseamplifier bank 246 _(a). The second mini-gap 354 _(b) separates thefirst ACT driver embedded sense amplifier bank 246 _(a) from the thirdRNL* driver embedded sense amplifier bank 146 _(c). The third mini-gap354 _(c) separates the second RNL* driver embedded sense amplifier bank146 _(b) from the second ACT driver embedded sense amplifier bank 246_(b). The fourth mini-gap 354 _(d) separates the second ACT driverembedded sense amplifier bank 246 _(b) from the fourth RNL* driverembedded sense amplifier bank 146 _(d).

Across the mini-gaps 354 _(a), 354 _(b), 354 _(c), 354 _(d), the RNL*driver embedded sense amplifier banks 146 _(a), 146 _(b), 146 _(c), 146_(d) and ACT driver embedded sense amplifier banks 246 _(a), 246 _(b),246 _(c), 246 _(d) are spaced far enough apart such that theabove-described n-well width problems are resolved. Since the mini-gaps354 _(a), 354 _(b), 354 _(c), 354 _(d) align with word line contactblocks 156 _(a), 156 _(b), 156 _(c), 156 _(d), the n-well width problemsare resolved using existing chip area. That is, by alternating RNL*driver embedded sense amplifier banks 146 _(a), 146 _(b), 146 _(c), 146_(d) and ACT driver embedded sense amplifier banks 246 _(a), 246 _(b),246 _(c), 246 _(d) in the horizontal direction extra spacing between thedriver transistors is not required. As such, the illustrated embodimentof the invention can implement large ACT and RNL* drivers withoutwasting precious area on the device 340.

Another advantage of the illustrated embodiment is that the gaps 350_(a), 350 _(b) and mini-gaps 354 _(a), 354 _(b), 354 _(c), 354 _(d) donot contain RNL* and ACT driver circuitry. Thus, the gaps 350 _(a), 350_(b) and mini-gaps 354 _(a), 354 _(b), 354 _(c), 354 _(d) have room forother functions required by the device 340. These functions may includethe circuitry needed to drive the RNL* to Vcc/2 and/or ACT to groundduring the precharge operations (described above with respect to FIGS. 7and 8). In addition, power straps, substrate and well contact blockscould be implemented in the gaps 350 _(a), 350 _(b) and mini-gaps 354_(a), 354 _(b), 354 _(c), 354 _(d). This may be problematic in theconventional DRAM devices.

FIG. 10 is a circuit diagram illustrating a portion of an exemplary bankof RNL* driver embedded sense amplifiers 346 constructed in accordancewith another embodiment of the invention. The illustrated bank 346comprises one RNL* driver embedded sense amplifier 146 and a pluralityof conventional sense amplifiers 46. The total number of senseamplifiers 46, 146 can be two hundred and fifty-six, but it should beappreciated that the invention is not limited to any specific number ofsense amplifiers 46, 146. In the illustrated embodiment, one RNL* driver191 is used to generate the n-sense amplifier activation signal RNL* forall of the sense amplifiers 46, 146 in the bank 346. The same n-senseamplifier activation signal RNL* can be routed to ACT embedded senseamplifiers if needed. Thus, the illustrated bank 346 need onlyincorporate one driver 191 to activate numerous n-sense amplifiers 60.

It should be appreciated that one RNL* driver 191 could be used togenerate the n-sense amplifier activation signal RNL* for two, four,eight or more of the sense amplifiers 46, 146 in the bank 346 (but lessthan all of the sense amplifiers 46, 146). In which case the bank 346would have multiple drivers 191, but fewer than one per sense amplifier46, 146, with each driver 191 being connected to N number of senseamplifier 46, 146, where N is greater than 1.

FIG. 11 is a circuit diagram illustrating a portion of an exemplary bankof ACT driver embedded sense amplifiers 446 constructed in accordancewith another embodiment of the invention. The illustrated bank 446comprises one ACT driver embedded sense amplifier 246 and a plurality ofconventional sense amplifiers 46. The total number of sense amplifiers46, 246 can be two hundred and fifty-six, but it should be appreciatedthat the invention is not limited to any specific number of senseamplifiers 46, 246. In the illustrated embodiment, one ACT driver 293 isused to generate the p-sense amplifier activation signal ACT for all ofthe sense amplifiers 46, 246 in the bank 446. The same p-sense amplifieractivation signal ACT can be routed to RNL* embedded sense amplifiers ifneeded. Thus, the illustrated bank 446 need only incorporate one driver293 to activate numerous p-sense amplifiers 70.

It should be appreciated that one ACT driver 293 could be used togenerate the p-sense amplifier activation signal ACT for two, four,eight or more of the sense amplifiers 46, 246 in the bank 446 (but lessthan all of the sense amplifiers 46, 246). In which case the bank 446would have multiple drivers 293, but fewer than one per sense amplifier46, 246, with each driver 293 being connected to N number of senseamplifier 46, 346, where N is greater than 1.

Thus, the embodiments of the invention physically alternate banks havingembedded RNL* and ACT drivers. In doing so, large RNL* and ACT driverscan be used since the sense amplifier bank has more room for the driversthen the mini-gaps. Proper sizing of these drivers will improve senseamplifier operation and operation of the DRAM device itself. Inaddition, by using the global word line scheme the bus size for then-sense amplifier activation signal RNL* and p-sense amplifieractivation signal ACT can be very small, which leaves more area on thechip for power buses and other control signals routed over the senseamplifiers. Another benefit of the invention is that the gaps andmini-gaps have room for other functions required by the DRAM device.These functions may include the circuitry needed to drive the RNL* ACTsignals during the precharge operations.

It should also be noted that the invention is not limited to theillustrated drivers 191, 293. That is, it is possible to have an RNL*driver 191 that uses p-channel MOSFET transistors or an ACT driver 293that uses n-channel MOSFET transistors if the application warranted sucha use. Thus, the invention is not to be limited solely to theillustrated n-channel RNL* driver 191 and p-channel ACT driver 293.

FIG. 12 illustrates a processor system 500 incorporating a DRAM memorycircuit 512 constructed in accordance with an embodiment of theinvention. That is, the DRAM memory circuit 512 comprises one of thephysically alternating sense amplifier driver schemes explained abovewith respect to FIGS. 9–11. The system 500 may be a computer system, aprocess control system or any other system employing a processor andassociated memory.

The system 500 includes a central processing unit (CPU) 502, e.g., amicroprocessor, that communicates with the DRAM memory circuit 512 andan I/O device 508 over a bus. 520. It must be noted that the bus 520 maybe a series of buses and bridges commonly used in a processor system,but for convenience purposes only, the bus 520 has been illustrated as asingle bus. A second I/O device 510 is illustrated, but is not necessaryto practice the invention. The system 500 may also include additionalmemory devices such as a read-only memory (ROM) device 514, andperipheral devices such as a floppy disk drive 504 and a compact disk(CD) ROM drive 506 that also communicates with the CPU 502 over the bus520 as is well known in the art. It should be noted that the memory 512may be embedded on the same chip as the CPU 502 if so desired.

While the invention has been described and illustrated with reference toexemplary embodiments, many variations can be made and equivalentssubstituted without departing from the spirit or scope of the invention.Accordingly, the invention is not to be understood as being limited bythe foregoing description, but is only limited by the scope of theappended claims.

1. A method of manufacturing a dynamic random access memory device, saidmethod comprising the acts of: fabricating a first bank of senseamplifiers, each sense amplifier comprising a first type of senseamplifier and a second type of sense amplifier; and fabricating a secondbank of sense amplifiers, each sense amplifier comprising a first typeof sense amplifier and a second type of sense amplifier, wherein saidfirst bank of sense amplifiers is fabricated to include at least onefirst driver circuit for activating said first type of sense amplifierin said first and second banks, and said second bank of sense amplifiersis fabricated to include at least one second driver circuit foractivating said second type of sense amplifier in said first and secondbanks.
 2. The method of claim 1, wherein said first bank is fabricatedto comprise a plurality of first driver circuits coupled to the firsttype of sense amplifiers in said first bank.
 3. method of claim 2,wherein each first driver circuit is associated with and connected to arespective first type of sense amplifier in said first bank.
 4. methodof claim 1, wherein said second bank is fabricated to comprise aplurality of second driver circuits coupled to the second type of senseamplifiers in said second bank.
 5. The method of claim 4, wherein eachsecond driver circuit is associated with and connected to a respectivesecond type of sense amplifier in said second bank.
 6. The method ofclaim 1, wherein said first bank is fabricated to comprise a singlefirst driver circuit that is electrically connected to all of said firsttype of sense amplifier in said first bank.
 7. The method of claim 1,wherein said second bank is fabricated to comprise a single seconddriver circuit that is electrically connected to all of said second typeof sense amplifier in said second bank.
 8. The method of claim 1,wherein said first bank is fabricated to comprise a plurality firstdriver circuits, wherein each first driver circuit is electricallyconnected to N number of said first type of sense amplifier in saidfirst bank, where N is greater than
 1. 9. The method of claim 1, whereinsaid second bank is fabricated to comprise a plurality second drivercircuits, wherein each second driver circuit is electrically connectedto N number of said second type of sense amplifier in said second bank,where N is greater than
 1. 10. The method of claim 1, further comprisingthe act of forming a gap between said first and second banks, said gapcomprising circuitry for providing at least one function required bysaid memory device.
 11. A method of fabricating a memory device, saidmethod comprising the acts of: fabricating a plurality of memory cellsorganized into sub-arrays; and fabricating a plurality of first andsecond banks of sense amplifiers for latching and amplifying memorycells in said sub-arrays, each sense amplifier comprising a first typeof sense amplifier and a second type of sense amplifier, each first bankof sense amplifiers including at least one first driver circuit foractivating said first type of sense amplifier in said first bank, eachsecond bank of sense amplifiers including at least one second drivercircuit for activating said second type of sense amplifier in saidsecond bank, and wherein said plurality of first and second banks arephysically alternated in a horizontal direction throughout said device.12. The method of claim 11, wherein said first bank is fabricated tocomprise a plurality of first driver circuits coupled to the first typeof sense amplifiers in said first bank.
 13. The method of claim 12,wherein each first driver circuit is associated with and connected to arespective first type of sense amplifier in said second bank.
 14. Themethod of claim 11, wherein said second bank is fabricated to comprise aplurality of second driver circuits coupled to the second type of senseamplifiers in said second bank.
 15. The method of claim 14, wherein eachsecond driver circuit is associated with and connected to a respectivesecond type of sense amplifier in said first bank.
 16. The method ofclaim 11, wherein said first bank is fabricated to comprise a singlefirst driver circuit that is electrically connected to all of said firsttype of sense amplifier in said first bank.
 17. The method of claim 11,wherein said second bank is fabricated to comprise a single seconddriver circuit that is electrically connected to all of said second typeof sense amplifier in said second bank.
 18. The method of claim 11,wherein said first bank is fabricated to comprise a plurality firstdriver circuits, wherein each first driver circuit is electricallyconnected to N number of said first type of sense amplifier in saidfirst bank, where N is greater than
 1. 19. The method of claim 11,wherein said second bank is fabricated to comprise a plurality seconddriver circuits, wherein each second driver circuit is electricallyconnected to N number of said second type of sense amplifier in saidsecond bank, where N is greater than
 1. 20. The method of claim 11,further comprising the act of fabricating a gap between said first andsecond banks, said gap comprising circuitry for providing at least onefunction required by said memory device.